Meshless Optimization of Triply Periodic Minimal Surface Based Two-Fluid Heat Exchanger.

Triply Periodic Minimal Surface (TPMS) is suitable for the heat transfer of fluids, but it is difficult to preserve the integrality of independent fluids channels during optimization. We present an effective meshless optimization framework of Triply Periodic Minimal Surface based two-fluid heat exchangers, which can be represented, analyzed and optimized using function representation. Our method is directly executed on continuous functions instead of time-consuming meshing (tetrahedral/hexahedral), thereby substantially promotes the efficiency and controllability. Specifically, a valid TPMS based two-fluid heat exchanger is first constructed by function expression. The heat exchanger consists of two independent fully-connected spaces, which are used to infill different fluids, respectively. The two spaces are divided by a smooth and continuous separating wall, which can be expressed by functions and inherits several good properties of TPMS, such as large heat exchange surface area, high-order smoothness, independence and full connectivity of each fluid channel, good mechanical properties and controllability. Then, we formulate the optimization model by controlling the thickness and topology of the separating wall directly using the function representation. Also, we adapt an efficient automatic optimization of the modeling problem by maximizing thermal energy exchange under maximum pressure drop constraint. Finally, we obtain an optimized two-fluid heat exchanger with continuous geometry changes and proper topology changes. To our knowledge, this is the first work to provide both design and optimization for the TPMS based two-fluid heat exchangers. Various numerical results demonstrate the effectiveness and efficiency of our method.